Incremental restores build on each other the way incremental backups build on the initial level-0 backup. Therefore, to restore an incremental backup, you need all the backup tapes from the level-0 backup through the last backup that you want to restore.
If you attempt an incremental restore to a storage system running Data ONTAP 6.2 or later from a storage system running a version earlier than Data ONTAP 6.2, the restore will fail. This is because there is a formatting code change between the two code releases. You need to run the full backup again after you have upgraded to Data ONTAP 6.2 or later.